The present invention relates to an output unit for laser in process machines utilizing laser such as a laser welding machine, a laser cutting machine and the like.
A laser process machine has an output unit for outputting a laser beam transmitted by an optical fiber from a laser device toward an object to be processed.
This laser output unit has a body connected on the extreme end of an optical fiber for transmitting a laser beam from a laser device. The body has a laser output port at the extreme end thereof. Also, the unit has a glass provided within said body to condense the introduced laser beam to emit it from the laser output port.
The laser output unit is often mounted on the extreme end of a robot hand. In this case, the robot hand is moved in accordance with a preset program to perform a predetermined processing work.
When such an output unit is used to weld, for example, an object to be welded such as metal, metal spatters molten by the laser beam spatter or fly in all directions and adhere to the glass, as a result of which the glass becomes stained.
To avoid this, a transparent protective glass is provided between the laser output port and the glass within the body.
If such a protective glass is provided, the glass is protected but the protective glass itself becomes stained. As the result, there gives rise to a problem in that the protective glass has to be often replaced, and in the case where the apparatus is introduced into a production line, the production line is stopped for replacing the protective glass.
An object of the present invention is, in applying a laser beam to an article to be processed to process it, to protect a protective glass from flying matter flied from a portion to be processed to minimize replacement of a protective glass.
The protective glass can be provided to protect the lens, but if the unit is used for a long period of time, the lens is unavoidably stained.
As the result, the lens is to be replaced. However, the following problems occur when the lens is replaced.
Since a focal length of lens used for the unit has an error of approximately 1%, a focal point of the laser beam becomes deviated when the lens is replaced. When the focal point of the laser beam is deviated, processing such as welding is not successfully carried out. It is therefore necessary to reset all the deviated data of the program set in the robot in advance so as to apply a focal point of laser beam to a work. Such an operation is cumbersome and takes much time.
Accordingly, in the laser output unit, it has been desired to eliminate adjustment resulting from replacement of lens.
As mentioned above, the object of the present invention is to minimize replacement of a protective glass. However, as the case may be, the protective glass has to be replaced.
In such a case, the production line using the laser process machine has to be stopped. Therefore, it is necessary to quickly replace a protective glass in order to enhance the production efficiency.
A conventional protective glass is secured interiorly of a unit body by an optical thread ring having slits on both ends and having threads in the periphery thereof as shown in FIG. 13.
Because of this, an exclusive-use screw driver as shown in FIG. 13 is required to remove the protective glass. This operation is cumbersome, and it took considerable time to remove and replace a protective glass. Therefore, it has been a task how replacing time for a protective glass is shortened.
Furthermore, when laser processing is carried out using a laser output unit, metal spatters molten by the laser beam and flied in all directions become stuck to not only the protective glass but also the internal surface of the laser output port. Accordingly, the necessity occurs to periodically clean the internal surface of the laser output port. In prior art, the internal surface of the laser output port has been cleaned by disassembling the body.
This cleaning method requires labor and time for the disassembly. In view of this, it has been long desired, in the laser output unit, to quickly clean the internal surface of the laser output port.